Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

Hylogomphus (Gomphidae) (Part of Common Clubtails) of Michigan - Identification

Formerly a part of the Gomphus (sensu lato) group, recent work (Ware et al. 2017) has supported the idea that Carle's (1986) subgeneric grouping merits generic ranking, and that species of Gomphus (sensu stricto) are an Eurasian grouping. Hylogomphus was originally named in Needham (1951) and Needham and Westfall (1955), but those two works did not follow (ICZN) rules of nomenclature by specifying a type species, which Needham, Westfall and May (2000) retroactively did. This genus is restricted to eastern North America. Adults are brightly patterned with greenish yellow thorax, mostly blackish abdomens. They are larger in size than most Phanogomphus but smaller than Gomphurus. Nymphs are visibly similar to Gomphurus but are smaller and have no middorsal groove on the middle abdomen segments.

(Taxonomic References: Carle 1986, Paulson 2011, Needham et al. 2014, Tennessen 2019, Walker 1958)

Adults

1a	a. Apical margin of male epiproct, in dorsal view, convex medially	Hylogomphus viridifrons(Hine)
	b. Penis vesicle of male slender in lateral view, about 2x as high as its length at midheight
	c. Subgenital plate of female as long as Ab9 sternum
	d. Face green to blue-green, usually without dark crossbands
1b	a. Apical margin of male epiproct, in dorsal view, straight or concave	Hylogomphus adelphus (Selys)
	b. Penis vesicle of male stout in lateral view, no more than 2x as high as its length at midheight
	c. Subgenital plate of female not as long as Ab9 sternum
	d. Face greenish, usually with prominent dark crossbands on transverse sutures
	also: Medial and apical portions of labrum heavily marked with black; male with anterior hamules each with anteromedial lobe ending in a pointed hook; female with elongate horns posterior to each end of the postocellar ridge, lateral margins of subgenital plate curving away from Ab9 sternum

Mature Nymphs

1a	a. Ab6 lateral margin with 8-11 stout spinules, several present in basal half	Hylogomphus viridifrons(Hine)
	b. End tooth of palpal blade usually 2x as long as adjacent tooth
	c. Ratio of paraproct ventral length : epiproct length usually ≤ 0.76
2b	a. Ab6 lateral margin with 0-6 stout spinules, none present in basal half	Hylogomphus adelphus (Selys)
	b. End tooth of palpal blade usually <2x as long as adjacent tooth
	c. Ratio of paraproct ventral length : epiproct length usually ≥ 0.76

Carle FC. 1986. The classification, phylogeny and biogeography of the Gomphidae (Anisoptera). I. Classification. Odonatologica 15: 275–326.
Needham JG, Westfall MJ, May ML. 2000. Dragonflies of North America, Revised Edition. Scientific Publishers, Gainesville, Florida, USA. xv + 939 p.
Needham JG, Westfall MJ, May ML. 2014. Dragonflies of North America. The Odonata (Anisoptera) fauna of Canada, the Continential United States, Northern Mexico and the Great Antilles. Third Edition. Scientific Publishers: Gainesville, Florida. xiv + 658.
Paulson D. 2011. Dragonflies and damselflies of the East. Princeton Field Guides. Princeton University Press, Pinceton, New Jersey, USA. 538 p.
Tennessen KJ. 2019. Dragonfly nymphs of North America: An Identification Guide. Springer International Publishing, Cham, Switzerland: xiv + 620 p.
Walker EM. 1958. The Odonata of Canada and Alaska, Volume 2. University of Toronto Press: Toronto, Ontario, Canada. xii + 318.
Ware JL, Pilgrim EM, May ML, Donnelly TW, Tennessen KJ. 2017. Phylogenetic relationships of North American Gomphidae and their close relatives. Systematic Entomology (in print).

Page created: July 17, 1998 - Last updated: April 23, 2020